The Influence of PtFe and Nano Aluminium Particles on the Anticorrosive Performance of Waterborne Coating

Abstract:

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In this paper, the anticorrosive performances of fastener coatings containing PTFE and/or
nano aluminum particles were investigated by using electrochemical impedance spectroscopy,
scanning electron microscope. The impedance spectroscopy was interpreted by means of analysis
equivalent electrical circuits. The coating capacitance of the films was monitored with the
immersion time to establish the water and ions permeability of these paint films. By comparison
with clear coating, PTFE and PTFE- nano aluminum pigmented coatings, the results indicated that
PTFE lowers the protective properties of the waterborne epoxy film although it can provide
lubricating effect. The nano aluminum powder presented the best beneficial effect and resulted in a
significant increase in corrosion resistance of the PTFE- nano aluminum composite coatings. The
corrosion-resistant mechanism of the effect of PTFE and nano aluminum particles in the coating is
discussed.

Abstract: Interest in nanomaterials has increased in recent years. This is due to the potential of size reduction to nanometric scale to provide properties of materials such as hardness, toughness, wear, and corrosion resistance. The current study is focused on WC-Co cermet coats, materials that are extensively used in applications requiring wear resistance. In this work, WC-17Co powder was thermally sprayed onto mild steel using High Velocity Oxy Fuel (HVOF) spray technique. The nanostructured specimen was produced from sprayed sample by heat-treating at 1100°C in a vacuum chamber. Their structures were studied by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Polarization and electrochemical impedance spectroscopy (EIS) tests were performed on the both types of coated samples in 3.5% NaCl solution. The amorphous phase in WC-17Co coating was transformed to crystalline phases by heat treatment at high temperatures. The heat treatment of these coatings at high temperature also resulted in partially dissolution of WC particles and formation of new crystalline phases. Generation of these phases produced the nanostructured coating with better mechanical properties. Comparative electro chemical test results showed that, the heat treatment could improve corrosion resistance of the nanostructured WC-17Co coat than the as sprayed coats.

Abstract: The organic-inorganic hybrid sol was prepared using an alkaline silica sol modified by acid-catalyzed hydrolytic polycondensation of methyltrimethoxysilane (MTMS) in a water-bath condition of 60oC, and then the water-based primer and topcoat were prepared through adding the pigments and nano-TiO2 suspension respectively. Through spraying and baking, the organicinorganic composite coating on the treated aluminum alloy was obtained. The optimum range of P/B (weight ratio of the pigment/binder) is determined between 1:1 and 1.5:1 by investigating the influence of the P/B of the primer on the adhesion and impact resistance of the coating. The microstructure of the coating was characterized by optical microscopy and scanning electron microscopy. The results show that there are lots of holes and lamellar structure in the primer coating and the obtained topcoat coating is uniform, smooth and dense. The coating of ~30 μm in thickness is mainly composed of three elements of silicon, aluminum and titanium, in which transition layer of ~10 μm is included. The physicochemical properties suggest that the coatings on aluminum alloy can meet the needs of finishing coating very well.

Abstract: Four different metal coatings of pure aluminum, aluminum zinc alloy, titanium, aluminum Titanium were prepared on the surface of X80 pipeline steel by the method of arc spraying.The microstructures and combination method between the four coatings and substrates were observed by means of metallurgical microscope.This paper use 3.5%(mass fraction) NaCl solution to simulate seawater. The corrosion potential, average corrosion rate and corrosion current density of the four metal coatings were studied through the immersion test, salt spray test and electrochemical experiment in 3.5% NaCl solution.According to the results,analyse the corrosion mechanism of different coatings compared to the different corrosion resistances. The results showed that the Al-Zn coating has the excellent comprehensive corrosion resistance.

Abstract: Ceramic oxide coatings were produced on pure titanium by plasma electrolytic oxidation in different electrolytes. The variation of coating thickness with applied voltages revealed coating almost kept a steady-state growth rate in electrolyte A and B, but not for electrolyte C. Numerous nodules occurred on the surface of the coatings at 200V in electrolyte A and B, and then nodules disappeared with the applied voltage increasing to 300V. There was no nodules occurred, and pore size was evidently different in electrolyte C. When the applied voltage was 300V, the coating formed in electrolyte C exhibited the highest corrosion potential and lowest corrosion current density in 3.5% NaCl aqueous solution.

Abstract: Micro-arc oxidation (MAO) coatings were synthesized on MB3 magnesium alloy substrate. Two different electrolyte (Ⅰ) and electrolyte (Ⅱ) were adopted, and the performance of ceramic coatings was compared. The morphology feature, phase composition, and chemical composition of the formed coatings were studied by metallographic microscope, scanning electron microscopy (SEM), energy disperse spectroscopy (EDS), XRD, respectively. The corrosion resistance of the coatings was evaluated by salt spray test. The research results show that, the starting and terminal voltage are different during the oxidation process, they are 220V and 375V in the electrolyte (Ⅰ), and 150V and 270 V in electrolyte (Ⅱ). After MAO, The sample surface in electrolyte (Ⅰ) is light gray, and looks tender and smooth. The ceramic coatings obtained in electrolyte (Ⅱ) are relative rough and white in colour. But MAO coatings obtained in electrolyte (Ⅱ) has higher deposition rate. Salt spray test show the corrosion resistance of samples obtained in electrolyte (Ⅱ) are better than those in electrolyte (Ⅰ), which is related to the thickness of the MAO coatings.